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Arya CK, Maurya S, Ramanathan G. Insight into the metabolic pathways of Paracoccus sp. strain DMF: a non-marine halotolerant methylotroph capable of degrading aliphatic amines/amides. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:125947-125964. [PMID: 38010547 DOI: 10.1007/s11356-023-30858-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/31/2023] [Indexed: 11/29/2023]
Abstract
Paracoccus sp. strain DMF (P. DMF from henceforth) is a gram-negative heterotroph known to tolerate and utilize high concentrations of N,N-dimethylformamide (DMF). The work presented here elaborates on the metabolic pathways involved in the degradation of C1 compounds, many of which are well-known pollutants and toxic to the environment. Investigations on microbial growth and detection of metabolic intermediates corroborate the outcome of the functional genome analysis. Several classes of C1 compounds, such as methanol, methylated amines, aliphatic amides, and naturally occurring quaternary amines like glycine betaine, were tested as growth substrates. The detailed growth and kinetic parameter analyses reveal that P. DMF can efficiently aerobically degrade trimethylamine (TMA) and grow on quaternary amines such as glycine betaine. The results show that the mechanism for halotolerant adaptation in the presence of glycine betaine is dissimilar from those observed for conventional trehalose-mediated halotolerance in heterotrophic bacteria. In addition, a close genomic survey revealed the presence of a Co(I)-based substrate-specific corrinoid methyltransferase operon, referred to as mtgBC. This demethylation system has been associated with glycine betaine catabolism in anaerobic methanogens and is unknown in denitrifying aerobic heterotrophs. This report on an anoxic-specific demethylation system in an aerobic heterotroph is unique. Our finding exposes the metabolic potential for the degradation of a variety of C1 compounds by P. DMF, making it a novel organism of choice for remediating a wide range of possible environmental contaminants.
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Affiliation(s)
- Chetan Kumar Arya
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Shiwangi Maurya
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Gurunath Ramanathan
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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Sanow S, Kuang W, Schaaf G, Huesgen P, Schurr U, Roessner U, Watt M, Arsova B. Molecular Mechanisms of Pseudomonas-Assisted Plant Nitrogen Uptake: Opportunities for Modern Agriculture. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:536-548. [PMID: 36989040 DOI: 10.1094/mpmi-10-22-0223-cr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Pseudomonas spp. make up 1.6% of the bacteria in the soil and are found throughout the world. More than 140 species of this genus have been identified, some beneficial to the plant. Several species in the family Pseudomonadaceae, including Azotobacter vinelandii AvOP, Pseudomonas stutzeri A1501, Pseudomonas stutzeri DSM4166, Pseudomonas szotifigens 6HT33bT, and Pseudomonas sp. strain K1 can fix nitrogen from the air. The genes required for these reactions are organized in a nitrogen fixation island, obtained via horizontal gene transfer from Klebsiella pneumoniae, Pseudomonas stutzeri, and Azotobacter vinelandii. Today, this island is conserved in Pseudomonas spp. from different geographical locations, which, in turn, have evolved to deal with different geo-climatic conditions. Here, we summarize the molecular mechanisms behind Pseudomonas-driven plant growth promotion, with particular focus on improving plant performance at limiting nitrogen (N) and improving plant N content. We describe Pseudomonas-plant interaction strategies in the soil, noting that the mechanisms of denitrification, ammonification, and secondary metabolite signaling are only marginally explored. Plant growth promotion is dependent on the abiotic conditions and differs at sufficient and deficient N. The molecular controls behind different plant responses are not fully elucidated. We suggest that superposition of transcriptome, proteome, and metabolome data and their integration with plant phenotype development through time will help fill these gaps. The aim of this review is to summarize the knowledge behind Pseudomonas-driven nitrogen fixation and to point to possible agricultural solutions. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Stefan Sanow
- Institute for Bio- and Geosciences, Plant Sciences (IBG-2), Forschungszentrum Juelich GmbH, Germany
- School of BioSciences, Faculty of Science, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Weiqi Kuang
- College of life and Environmental Sciences, Hunan University of Arts and Science, China
| | - Gabriel Schaaf
- Institute of Crop Science and Resource Conservation, University of Bonn, 53115 Bonn, Germany
| | - Pitter Huesgen
- Central institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Juelich GmbH, Germany
| | - Ulrich Schurr
- Institute for Bio- and Geosciences, Plant Sciences (IBG-2), Forschungszentrum Juelich GmbH, Germany
| | - Ute Roessner
- Research School of Biology, The Australian National University, Acton, 2601 Australian Capital Territory, Australia
| | - Michelle Watt
- School of BioSciences, Faculty of Science, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Borjana Arsova
- Institute for Bio- and Geosciences, Plant Sciences (IBG-2), Forschungszentrum Juelich GmbH, Germany
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Schulz-Mirbach H, Müller A, Wu T, Pfister P, Aslan S, Schada von Borzyskowski L, Erb TJ, Bar-Even A, Lindner SN. On the flexibility of the cellular amination network in E. coli. eLife 2022; 11:77492. [PMID: 35876664 PMCID: PMC9436414 DOI: 10.7554/elife.77492] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/22/2022] [Indexed: 12/03/2022] Open
Abstract
Ammonium (NH4+) is essential to generate the nitrogenous building blocks of life. It gets assimilated via the canonical biosynthetic routes to glutamate and is further distributed throughout metabolism via a network of transaminases. To study the flexibility of this network, we constructed an Escherichia coli glutamate auxotrophic strain. This strain allowed us to systematically study which amino acids serve as amine sources. We found that several amino acids complemented the auxotrophy either by producing glutamate via transamination reactions or by their conversion to glutamate. In this network, we identified aspartate transaminase AspC as a major connector between many amino acids and glutamate. Additionally, we extended the transaminase network by the amino acids β-alanine, alanine, glycine, and serine as new amine sources and identified d-amino acid dehydrogenase (DadA) as an intracellular amino acid sink removing substrates from transaminase reactions. Finally, ammonium assimilation routes producing aspartate or leucine were introduced. Our study reveals the high flexibility of the cellular amination network, both in terms of transaminase promiscuity and adaptability to new connections and ammonium entry points. Nitrogen is an essential part of many of the cell’s building blocks, including amino acids and nucleotides, which form proteins and DNA respectively. Therefore, nitrogen has to be available to cells so that they can survive and grow. In nature, some microorganisms convert the gaseous form of nitrogen into ammonium, which then acts as the nitrogen source of most organisms, including bacteria, plants and animals. Once cells take up ammonium, it is ‘fixed’ by becoming part of an amino acid called glutamate, which has a so-called ‘amine group’ that contains a nitrogen. Glutamate then becomes the central source for passing these amines on to other molecules, distributing nitrogen throughout the cell. This coupling between ammonium fixation and glutamate production evolved over millions of years and occurs in all organisms. However, the complete metabolic network that underlies the distribution of amines remains poorly understood despite decades of research. Furthermore, it is not clear whether ammonium can be fixed in a way that is independent of glutamate. To answer these questions, Schulz-Mirbach et al. used genetic engineering to create a strain of the bacterium E. coli that was unable to make glutamate. These mutant cells could only grow in the presence of certain amino acids, which acted as alternative amine sources. Schulz-Mirbach et al. found that enzymes called transaminases, and one called AspC in particular, were required for the cells to be able to produce glutamate using the amine groups from other amino acids. Notably, Schulz-Mirbach et al. showed that AspC, which had previously been shown to use an amino acid called aspartate as a source of amine groups, is indispensable if the cell is to use the amine groups from other amino acids – including histidine, tyrosine, phenylalanine, tryptophan, methionine, isoleucine and leucine. Schulz-Mirbach et al. also discovered that if they engineered the E. coli cells to produce transaminases from other species, the repertoire of molecules that the cells could use as the source of amines to generate glutamate increased. In a final set of experiments, Schulz-Mirbach et al. were able to engineer the cells to fix ammonium by producing aspartate and leucine, thus entirely bypassing the deleted routes of glutamate synthesis. These data suggest that fixing ammonium and distributing nitrogen in E. coli can be very flexible. The results from these experiments may shed light on how cells adapt when there is not a lot of ammonium available. Moreover, this study could advance efforts at metabolic engineering, for example, to create molecules through new pathways or to boost the production of amino acids needed for industrial purposes.
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Affiliation(s)
| | - Alexandra Müller
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Tong Wu
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Pascal Pfister
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Selçuk Aslan
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | | | - Tobias J Erb
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Arren Bar-Even
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Steffen N Lindner
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
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Zeng Q, Ding X, Wang J, Han X, Iqbal HMN, Bilal M. Insight into soil nitrogen and phosphorus availability and agricultural sustainability by plant growth-promoting rhizobacteria. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:45089-45106. [PMID: 35474421 DOI: 10.1007/s11356-022-20399-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/19/2022] [Indexed: 02/08/2023]
Abstract
Nitrogen and phosphorus are critical for the vegetation ecosystem and two of the most insufficient nutrients in the soil. In agriculture practice, many chemical fertilizers are being applied to soil to improve soil nutrients and yield. This farming procedure poses considerable environmental risks which affect agricultural sustainability. As robust soil microorganisms, plant growth-promoting rhizobacteria (PGPR) have emerged as an environmentally friendly way of maintaining and improving the soil's available nitrogen and phosphorus. As a special PGPR, rhizospheric diazotrophs can fix nitrogen in the rhizosphere and promote plant growth. However, the mechanisms and influences of rhizospheric nitrogen fixation (NF) are not well researched as symbiotic NF lacks summarizing. Phosphate-solubilizing bacteria (PSB) are important members of PGPR. They can dissolve both insoluble mineral and organic phosphate in soil and enhance the phosphorus uptake of plants. The application of PSB can significantly increase plant biomass and yield. Co-inoculating PSB with other PGPR shows better performance in plant growth promotion, and the mechanisms are more complicated. Here, we provide a comprehensive review of rhizospheric NF and phosphate solubilization by PGPR. Deeper genetic insights would provide a better understanding of the NF mechanisms of PGPR, and co-inoculation with rhizospheric diazotrophs and PSB strains would be a strategy in enhancing the sustainability of soil nutrients.
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Affiliation(s)
- Qingwei Zeng
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China.
| | - Xiaolei Ding
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Jiangchuan Wang
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Xuejiao Han
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Hafiz M N Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, 64849, Monterrey, Mexico
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
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Wise L, Marecos S, Randolph K, Hassan M, Nshimyumukiza E, Strouse J, Salimijazi F, Barstow B. Thermodynamic Constraints on Electromicrobial Protein Production. Front Bioeng Biotechnol 2022; 10:820384. [PMID: 35265598 PMCID: PMC8899463 DOI: 10.3389/fbioe.2022.820384] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/14/2022] [Indexed: 02/03/2023] Open
Abstract
Global consumption of protein is projected to double by the middle of the 21st century. However, protein production is one of the most energy intensive and environmentally damaging parts of the food supply system today. Electromicrobial production technologies that combine renewable electricity and CO2-fixing microbial metabolism could dramatically increase the energy efficiency of commodity chemical production. Here we present a molecular-scale model that sets an upper limit on the performance of any organism performing electromicrobial protein production. We show that engineered microbes that fix CO2 and N2 using reducing equivalents produced by H2-oxidation or extracellular electron uptake could produce amino acids with energy inputs as low as 64 MJ kg−1, approximately one order of magnitude higher than any previous estimate of the efficiency of electromicrobial protein production. This work provides a roadmap for development of engineered microbes that could significantly expand access to proteins produced with a low environmental footprint.
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Affiliation(s)
- Lucas Wise
- > Department of Food Sciences, Cornell University, Ithaca, NY, United States
| | - Sabrina Marecos
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
| | - Katie Randolph
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
| | - Mohamed Hassan
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
| | - Eric Nshimyumukiza
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
| | - Jacob Strouse
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
| | - Farshid Salimijazi
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
| | - Buz Barstow
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
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RNA-Seq Provides New Insights into the Gene Expression Changes in Azoarcus olearius BH72 under Nitrogen-Deficient and Replete Conditions beyond the Nitrogen Fixation Process. Microorganisms 2021; 9:microorganisms9091888. [PMID: 34576783 PMCID: PMC8467165 DOI: 10.3390/microorganisms9091888] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 11/17/2022] Open
Abstract
Azoarcus olearius BH72 is an endophyte capable of biological nitrogen fixation (BNF) and of supplying nitrogen to its host plant. Our previous microarray approach provided insights into the transcriptome of strain BH72 under N2-fixation in comparison to ammonium-grown conditions, which already indicated the induction of genes not related to the BNF process. Due to the known limitations of the technique, we might have missed additional differentially expressed genes (DEGs). Thus, we used directional RNA-Seq to better comprehend the transcriptional landscape under these growth conditions. RNA-Seq detected almost 24% of the annotated genes to be regulated, twice the amount identified by microarray. In addition to confirming entire regulated operons containing known DEGs, the new approach detected the induction of genes involved in carbon metabolism and flagellar and twitching motility. This may support N2-fixation by increasing energy production and by finding suitable microaerobic niches. On the other hand, energy expenditures were reduced by suppressing translation and vitamin biosynthesis. Nonetheless, strain BH72 does not appear to be content with N2-fixation but is primed for alternative economic N-sources, such as nitrate, urea or amino acids; a strong gene induction of machineries for their uptake and assimilation was detected. RNA-Seq has thus provided a better understanding of a lifestyle under limiting nitrogen sources by elucidating hitherto unknown regulated processes.
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Lu C, Yang Z, Liu J, Liao Q, Ling W, Waigi MG, Odinga ES. Chlorpyrifos inhibits nitrogen fixation in rice-vegetated soil containing Pseudomonas stutzeri A1501. CHEMOSPHERE 2020; 256:127098. [PMID: 32470732 DOI: 10.1016/j.chemosphere.2020.127098] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/30/2020] [Accepted: 05/14/2020] [Indexed: 05/28/2023]
Abstract
Chlorpyrifos, a common organophosphorus pesticide, is widely used for agricultural pest control and can inhibit nitrogen-fixing bacteria biomass in paddy. In this study, the additions of chlorpyrifos (1 and 8 mg kg-1) to soil, with or without Pseudomonas stutzeri A1501, resulted in a significant decrease in nitrogen fixation, despite insignificant effects on the abundances of P. stutzeri A1501 and bacteria in soil. Toxic effect of chlorpyrifos on P. stutzeri A1501 nitrogenase activity in medium was also observed, accompanied by a significant reduction in the expression of nitrogen-fixing related genes (nifA and nifH). Furthermore, rhizosphere colonization and biofilm formation by P. stutzeri A1501 were repressed by chlorpyrifos, leading to decreased nitrogenase activity in the rhizosphere. Biofilm formation in medium was inhibited by bacterial hyperkinesis and reduction of extracellular polymeric substance, including exopolysaccharides and proteins. Together, these findings showed that chlorpyrifos-induced production of reactive oxygen species (ROS) which was directly responsible for reduced nitrogenase activity in the medium, soil, and rhizosphere by inhibiting the expressions of nitrogen-fixing related genes. Furthermore, the inhibition of biofilm formation by chlorpyrifos or ROS likely aggravated the reduction in rhizospherere nitrogenase activity. These findings provide potentially valuable insights into the toxicity of chlorpyrifos on nitrogen-fixing bacteria and its mechanisms. Furthermore, for sustainable rice production, it is necessary to evaluate whether other pesticides affect nitrogen fixation and select pesticides that do not inhibit nitrogen fixation.
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Affiliation(s)
- Chao Lu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhimin Yang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Juan Liu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qihang Liao
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wanting Ling
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Michael Gatheru Waigi
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Emmanuel Stephen Odinga
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
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